Evaluation of benzyl-substituted DTPA analogues as decorporation agents of radionuclides

Optically active and racemic Bn-DTPA analogues were evaluated for potential decorporation of radioactive lanthanides. Complexation kinetics of the Bn-DTPA analogues with Sr(II), Ce(III), and Ce(IV) was measured using arsenazo III-based spectroscopic method. The Bn-DTPA analogues effectively and rapidly bound to Sr(II), Ce(III), and Ce(IV). Bn-DTPA was orally administered to mice and evaluated for decorporation of ⁸⁵Sr and compared to that of the clinically available Ca(II)-DTPA. (rac)-Bn-DTPA removed ⁸⁵Sr in mice more efficiently than DTPA. The Bn-DTPA analogues are promising decorporation agents for potential removal of ⁹⁰Sr, ¹⁴⁴Ce, and ¹⁴¹Ce.